Reverse Osmosis Systems

HOH Systems©, design prefiltration and Reverse Osmosis systems according to individual requirements and volumes working of comprehensive water analysis. Various technologies are applied to answer a full spectrum of water contaminants, energy, design, or budget constraints.

Many RO systems fail due to inaccurate pre-treatment processes or flaws in design flow calculations and managing of conditions that will damage the membranes. HOH Systems can assist in correcting these conditions and revitalizing membranes.

^{Reverse Osmosis Explained}

NOTE: The following serves as information only. HOH Systems do not take any exclusive position on this ever-developing technology. General examples and laymen terms are used as a means of keeping the information digestible and enjoyable.

Reverse osmosis (RO) is a process of purification often used to remove chemicals from water. It works by using pressure to force a solution through a membrane, retaining the solute on one side and allowing the pure solvent to pass to the other side. This is the reverse of the normal osmosis process, which is the natural movement of solvent from an area of low solute concentration, through a membrane, to an area of high solute concentration where no external pressure is applied.

The difference between RO and Filtration

The principal removal mechanism in filtration is particle straining, while RO is better described as parting two streams from a solution into a clean and a waste stream.

This solution prepared for the RO process is referred to as “concentrate”, while the purified stream is the “permeate” and the reject stream is called the “waste” or “reject”.

Particle filtration can typically take place in stepped down sizes from 50, 20, 10, 5, 1 and 0,5 micron in day to day commercial applications. Reverse osmosis, however, can separate to atomic radius sizes. That is as little as 0,001 microns.

As illustration of the above-mentioned sizes, consider the following:

If the diameter of a single grain of beach sand = Distance between Johannesburg and Cape Town (1 400 km)

then the

Virus = Athletics track

and the

Metal ion = Springbok Lock

(all by himself in the middle of the Newlands rugby field, somewhere on the edge of a sand grain that has Johannesburg on its opposite end )

The graphics below are a further attempt to illustrate the scale used in RO water purification

Only the beach sand grain and the hair are visible to the human eye.

Stepping down a scale by removing the beach sand from the graphic shows how the 3 smallest items are still remarkably “unscalable” on this chart because they are simply too small to illustrate here.

Even after removing the beach sand: Viruses, pesticides/herbicides and metal ions are still not visible on this scale.

The above examples show how RO can be used to clean up the worst of contaminated water right down to where herbicide, pesticides, hormones, metals and other health-threatening elements are removed. In practice, however, a fraction of the living bacteria can pass by the RO membrane through minor imperfections or bypass it entirely through small leaks in the surrounding seals. Therefore, reverse osmosis systems may include additional water treatment stages that use ultraviolet light or ozone to ensure water safety. However, RO water has been cleaned to a point where, if any contaminants are left in the water, the concentration is so low that it does not pose a danger to health.

This brings us to the BIG DISCUSSION.

Does RO strip minerals?

Some may argue that RO strips minerals that are important to human health from drinking water.

This may be a valid concern in some scenarios. Where the end user prefers, HOH Systems will install re-mineralization or blend systems and devices in accordance with current best practices.

IMPORTANT TO NOTE: With RO, everything, known and unknown, has been removed and that is a great insurance in the contaminated world we live in today. Re-introduction of any combination of salts and minerals must be done with caution and only with confidence that the source of these re-mineralization systems is of a known, reputable, and certified nature.

Here is an example of the amount of minerals lost when drinking 2 litres per day of RO water with a total dissolved solid (TDS) count of 001 vs tap water with a TDS of 120.

TDS 001 = 1 mg/litre of salts and minerals. At 2 litres of water per day, this translates into 2 mg/day.
TDS 120 = 120 mg/litre of salts and minerals. At 2 litres of water per day, this translates into 240 mg/day.

While this may seem like a large difference, at 238 mg/day, on a relative scale it becomes minor.

A pinch of salt (¼ g) = 250 mg
One teaspoon (5 g) = 5 000 mg

Keep in mind that the pinch of minerals lost is obtainable from a healthy diet. However, the final decision remains with the end user and is fully supported by HOH Systems.